8.1: Vehicles, Capital Ships, and Fuel Consumption
If a group of characters is going to be doing a lot of traveling during the course of an adventure, they are probably going to want to use a vehicle. There are many advantages of using vehicles in terms of the amount of supplies that can be hauled and the amount of time it takes to travel over just hoofing it. In some cases a vehicle is required just to make the journey possible, such as when a character group must go visit another planet. When using vehicles for travel, there are three crucial questions that must be answered: how far can the vehicle travel in a given period of time, how far did the vehicle travel in that same period of time and how much fuel did the vehicle use in that same period of time. This sub-Chapter focuses on the third question. NOTE: for the sake of brevity and except where otherwise noted, capital ships will be considered space vehicles for purposes of this discussion. A Quick Word about Fuel Vehicles require fuel. There's no real way around this fact; even the most primitive of machines require some kind of fuel in order to function (though in this case the "fuel" is usually provided by a living being). Vehicles in WCRPG are no exception to this fundamental rule: without fuel, a vehicle will go nowhere in a real hurry. A fundamental question that arises when operating a vehicle is whether or not it will have sufficient fuel to make it to its destination, considering any tasks its crew has to perform along the way. Most Starfaring Age vehicles generate thrust and power either through fusion or matter/antimatter reactions. Fuels for these reactions often include the use of common fissile materials such as uranium or plutonium (whose fission reactions are used to provide the initial energetic kick required to start the fusion reaction) as well as fusible materials, usually deuterium, tritium and/or an advanced mixed-oxide material. Antimatter is created in specialized particle accelerators and requires the use of the same materials used for fusion reactions. A sufficient quantity of antimatter is capable of providing enough energy to power a capital ship's Akwende drive; it stands to reason that even a small quantity of antimatter could provide virtually unlimited fuel for a small craft, though only a few vehicles in the Wing Commander continuity (such as the F-107 Dragon) are even capable of utilizing antimatter as a power source. Non-Starfaring Age vehicles will utilize other fuel sources; Metal Age vehicles in particular may rely heavily on wind power while Industrial Age vehicles will use fossil fuels, solar, wind or nuclear sources. These are of course just a few possible fuel sources; GMs are free to come up with their own sources of fuel for use in their adventures. In practical terms, fuel is fuel; it doesn't matter so much what kind of fuel a vehicle has as much as that it actually has something. The amount of fuel a vehicle had remaining was a somewhat important aspect of the original games; fuel level determined whether or not the player could use their afterburner or jump to the next system. In WCRPG, keeping track of fuel consumption is no less important. In fact, it is more so; running out of fuel is a Bad Thing that, depending upon the situation, can have a number of nasty effects (the player might be forced to march back to their ship, make a distress call, have to continue fighting on reserve power only or plummet out of orbit). To keep track of how much fuel a vehicle has remaining, WCRPG utilizes a system of fuel points. Expenditure of these points allows the vehicle to perform one or more actions. Fuel points do not equate to any specific amount of a fuel substance; simply put, there isn't enough data to definitively say what the actual fuel capacity is for most of the extant craft in the Wing Commander Universe. For reference, all vehicles have a number of fuel points equal to ten times their Size Class provided they incorporate Engines; the vehicle carries no fuel otherwise. Certain accessories such as Fuel Tanks and Drop Tanks may augment the number of fuel points a vehicle has at its disposal. In addition to their regular fuel "tank", vehicles have a very small reserve for use in the event of an emergency situation. This reserve is generally no larger than 5% (rounded up) of the vehicle's normal fuel capacity. While that isn't a lot, it may give a vehicle just enough reach to make it to a refueling depot or at least to get it to a safe stop on terra firma. Switching to the reserve is automatic in the event the main tank runs dry. In the event a vehicle's fuel completely runs out, what happens to it depends largely on the vehicle's chassis and where it is. Most land vehicles will generally start decelerating and come to an eventual stop. Skimmers are an exception; when they run out of fuel their repulsor cuts out, which means that they immediately drop to the ground and as likely as not are subjected to a collision and skid (this counts as a Sideswipe attempt against the Skimmer with an automatic success; see Chapter 9.3 for details). Sea vehicles will start to drift along on any currents the vehicle was experiencing at the time it ran out of fuel. Any submerged submarine will lose ballast control and begin Taking on Water (see Chapter 9.3). Air vehicles will automatically Stall (see Chapter 9.3) as will any space vehicle in atmosphere. A space vehicle in the middle of atmospheric re-entry will lose control over the process (see Chapter 8.3). A space vehicle in planetary orbit will begin an uncontrolled atmospheric re-entry as soon as its orbit decays, though any occupants will likely run out of life support well before the vehicle actually begins atmospheric re-entry (see Chapter 12.3). Finally, a space vehicle in space will drift; given the vastness of space, it's unlikely that anyone friendly would chance upon the vehicle and give its crew some fuel. Fightercraft are an exception; when their fuel runs out, they can continue on at cruising speed - they may not engage their afterburners, however. Places where a vehicle's fuel supply may be replenished depend upon the groundwork laid out for an adventure by the GM. The GM may decide to make it possible to fuel up only at a home base, at a friendly port, in mid-flight or somewhere else entirely. Fuel Efficiency for Subluminal Travel A vehicle's fuel efficiency is the ratio of the amount of fuel it expends to a given distance of travel. In WCRPG, there are three key factors that affect a vehicle's fuel efficiency: the vehicle's base fuel efficiency as determined by its Engine Class and augmented with certain accessories, the difficulty of the terrain through which a vehicle is passing relative to other possible terrain types (known, perhaps unsurprisingly, as terrain difficulty) and the severity of the current weather. The distance considered when determining a vehicle's fuel efficiency (called the navigational unit distance) is solely dependent upon the vehicle's chassis (see Chapters 6.2.1 and 7.2.1). More specifically, it's dependent upon which of the four general terrain categories in which the vehicle is designed to operate: land, sea, air or space. The navigational unit distance for a vehicle is exactly five times the distance represented by its combat range increment (see Chapter 9.3). For land vehicles, this distance is five kilometers. Sea vehicles use a navigational unit distance of 50 kilometers, while for air vehicles it's 100 kilometers; space vehicles in atmosphere are treated as air vehicles, so they also use the 100 kilometer distance in that case. For star-borne space vehicles and capital ships, the increment is 5,000 kilometers unless an active Impulse Drive is being used, in which case it's 0.1 AU (fifteen million kilometers). Fuel efficiency for all superluminal travel follows its own set of rules as outlined later in this sub-Chapter. Because of the diversity of vehicles that exist in WCRPG, terrain effects on fuel efficiency are determined using a set of categorical difficulties as opposed to specific terrains; this is because terrain that might be a given difficulty for one type of vehicle might be drastically easier or harder to negotiate for a different vehicle type. Muddy Terrain is a good example. Most land vehicles might have a tough time negotiating muddy terrain (for the sake of argument let's say it's a Difficult terrain difficulty level for them) but a Skimmer would be able to fly right over it (Extremely Easy) as would most air and space vehicles. Sea vehicles wouldn't be able to negotiate mud at all (Impossible); that's three different terrain difficulty levels all describing "muddy", a single type of terrain. The following table describes the various terrain difficulty categories and provides a list of example terrains for each category for each type of vehicle. This table is meant as a general guide only; GMs are welcome to use whatever terrain difficulty they feel is most appropriate to the situation at hand. In addition to having an effect on fuel efficiency, terrain difficulty will always have an effect on any piloting Checks made in order to negotiate the given terrain (as discussed in Chapters 8.2, 8.3, and 8.4). Weather also plays a crucial role in determining a vehicle's fuel efficiency. Adverse weather conditions often force a vehicle's engines to work harder in order to achieve the same level of performance possible in calmer conditions. Weather can affect a vehicle's fuel efficiency regardless of the four general terrain categories in which the vehicle is designed to operate; even vehicles operating in space can be affected by "space weather" (solar and magnetic storms, etc.) if the GM decides to incorporate such phenomena into an adventure. For purposes of this discussion, only planetary weather phenomena will be discussed. WCRPG utilizes four categories of weather for determining its effects on fuel efficiency: Calm, Light, Heavy and Severe. Calm weather generally means little to no adverse weather conditions (land vehicle examples include clear skies, overcast skies with no precipitation, mist, haze or fog). Light weather refers to weather that has a comparatively minor impact on fuel efficiency (for sea and air vehicles, this includes overcast skies, mist, haze or fog; land vehicles include light to moderate rain or snow). Heavy weather refers to weather that has a significant impact on fuel efficiency though it is not severe enough to cause significant structural damage (this includes heavy rain, snow or any kind of precipitation for sea and air vehicles). Finally, Severe weather is any kind of weather that is capable of causing structural damage to a vehicle and has a major negative impact on its fuel efficiency regardless of whether or not any actual damage occurs (this includes any kind of storm). Earthquakes and volcanic eruptions are considered storms for purposes of determining fuel efficiency even though they are technically not weather phenomena; see Chapter 8.2 for details on the effects of both storms and seismic activity. The following chart outlines the possible fuel efficiencies for any given hour of travel; the listings are in fuel points expended per navigational units of distance traveled. To read the table, the GM must find the cell that corresponds to the intersection of the column corresponding to the vehicle's base fuel efficiency with the row that corresponds to the current terrain difficulty level. Four fuel efficiency ratings are given inside each cell, each one corresponding to a specific type of weather; Calm weather is listed on the top, then Light, then Heavy and finally Severe on the bottom. For example, a land vehicle with a Fourth Class Engine is traveling in sand when a thunderstorm kicks up. A Fourth Class Engine has a base fuel efficiency of twenty percent and sand is considered Moderate terrain using the example table listed above. Looking in the cell where these two factors intersect, the fuel efficiencies are 1/1 for everything from Calm to Heavy weather and 2/1 for Severe weather; a thunderstorm is considered Severe weather, so the 2/1 rating will be used. For that hour, the vehicle will consume two fuel points for every five kilometers it travels (due to it being a land vehicle). Fuel Efficiency for Superluminal Travel Traveling at faster-than-light speed uses its own set of rules for determining fuel efficiency, though the actual difference between how it's determined in superluminal and subluminal travel is fairly minimal. Of the factors that affect fuel efficiency in subluminal travel, usually only the craft's Engine has an effect; the terrain difficulty for jumpspace is usually treated as Extremely Easy to negotiate and the weather is usually treated as Calm. It takes more energy to move a vehicle at faster-than-light speeds than it does to move in normal space and a substantially larger spatial unit distance is involved in general, which is why a unique table is needed. For all vehicles traveling at faster-than-light speeds, the navigational unit distance is either one jump (for D-Drives and Akwende Drives) or one hop (for Morvan Drives). This is true regardless of the vehicle's chassis; an FTL-capable shuttle and an armored battlecruiser will both use one jump as their navigational unit distance. There are multiple methods of determining the exact distance a vehicle travels between points in space when it makes a hop; these methods are discussed in Chapter 8.4. The following chart lists the fuel efficiency ratings for the major classes of Faster-Than-Light drive systems in the Wing Commander universe: Akwende Drive, Morvan Drive and D-Drive. To read the table, the GM may find the intersection between the column corresponding to the vehicle's base fuel efficiency with the row that corresponds to the type of drive system being utilized. Each cell lists the number of fuel points expended in the FTL transit; occurrences of "SC" in the table reference the vehicle's Size Class. For example, a Size Class 15 capital ship with a Class Five Engine is making an FTL transit. A Class Five Engine has a base efficiency of 25%. We can look across the columns to find the amount of fuel expended for the various drive types. Akwende Drives are in the first column; the ship would expend seventeen fuel points in the jump if it had an Akwende Drive since it is an SC 15 ship. Morvan drives are located in the second column. If this type of drive were being used, the ship would expend six fuel points. If the ship was equipped with a D-Drive, we'd look up the third column; the ship would expend eleven fuel points in the jump. The only difference between the various drive systems is, of course, the amount of distance covered in the transit. Note that the table above assumes the use of a matter/antimatter power plant. Should the vehicle in question employ a fusion power plant, the indicated amount of fuel expenditure must be multiplied by eight. Craft with fission-based or more primitive power supplies may not make FTL transits. All FTL transits require a minimum of at least one fuel point even if an amount of fuel equal to zero or less is indicated. It is also possible that a craft may have sufficient time to regain any lost fuel points from a hop or jump (provided the ship is equipped with refueling technology such as a ramscoop) resulting in a net-zero fuel expenditure. It may be that a GM wants to include a situation in an adventure wherein the basic assumptions about interstellar terrain and weather aren't true. In that case, the GM may simply use the fuel efficiency ratings for a lower Engine efficiency; a good rule of thumb is to go down one level (a 5% drop, or a 10% drop for high-efficiency Engines) for the first level increase in terrain difficulty and down an additional level for each two levels after that (go down one level for Very Easy, two levels for Moderate, three levels for Very Difficult and four levels for Impossible terrain). The same drops can be applied for increasingly severe space weather (down one level for Light, two levels for Severe). The 5% fuel efficiency level is the lowest possible level; if the 5% level is already indicated and further decreases are also indicated, ignore them. ---- NEXT: 8.2 Planetary Exploration PREVIOUS: 8.0 Navigation TOP ---- Category:WCRPG